In Part 1 we explained how the tones of most real instruments can be reduced to patterns of harmonics, which can be generated using sine, saw, square or pulse waveforms. This month, we consider the sonic raw materials needed to imitate unpitched percussion.

In Part 1 of this (63-part) series exploring the world of subtractive synthesis, Gordon Reid goes right back to basics. What are waveforms and harmonics, where do they come from, and how does the theory relate to what we actually hear?

It was the best-selling single of last year, and signalled a radical change of musical direction for Cher — complete with bizarre vocal processing. Yet, surprisingly, it was produced in a small studio in West London. Sue Sillitoe relates the astonishing tale of 'Believe'.